Improvement in air-compressing pumps



J. N. DENNISSON, OF NEWARK, ANEW JERSEY, ASSIGNOR TO HIMSELF, F. H. GOULD, AND R. J. GOULD, OF SAME PLAGE.

IMPROVEMENT IN AIR-COMPRESSING PUMPS.

Specification forming part of Letters Patent No. 59, l 24, dated October 23, 1866.

To all whom t may concern.'

Be it known that I, J. N. DENNIssoN, ol Newark, in the county of Essex and State of New Jersey, have invented a new and Improved Pump for CompressingAir, 8vo.; and I do hereby declare that the following is a full, clear, and exact description thereof', which will enable others skilled in the art to make and use the same, reference being had to the accompanyingdrawings, forming part of this specification, in which- Figure 1 represents a vertical section of this invention. Fig. 2 is a horizon tal section of the same. l

Similar letters of reference indicate like parts.

This invention consists in the employment or use, in an air-pump, of two cylinders of unequal diameters, fitted with pistons which operate in opposite directions,and communicating with each other by means of a pipe provided with valves at both ends, the valve next to the largest cylinder being made to open outward and that next to the slnaller cylinder inward,in combination with a suitable supplypipe extending to the large cylinder and a discharge-pipe emanating from the small cylinder, each pipe being provided with a valve, that in the supply-pipe opening inward and that in the discharge-pipe opening outward, in such a manner that when the piston in the large cylinder descends the air contained in the same is compressed in the small cylinder,

and on the downstroke of the piston in the small cylinder the compressed air contained therein is forced'down into the reservoir containing compressed air, or'into the well containing gases, under a high pressure, and thereby much power is saved. For instance, if the area ot' the. large piston -is twenty square inches`and that of the small piston tive square inches, the stroke of both being the same, and if the pressure of the gases in the oil-well is two hundred and forty pounds tothe square inch, it would require a power capable` of overcoming a resistance of forty-eight hundred pounds to force the air from the large cylinder directly into the well; whereas the power requisite to force the air into the small cylinder has to overcome a resistance which never exceeds twelve hundred pounds,and the power requisite to force the same quantity of air from the small cylinder into the Well is equal to a resistance of 5X240=1200 pounds, so that the power requisite to work the doublecylinder pump is atleast four times less than that requisite to work a pump with a single .cylinder which will throw the same quantity small piston is several times less than that of the large piston.

rlhe piston-rod b of the large piston connects with a crank, o, and the piston-rod d of the small piston with a crank, e, and these are mounted on the sa-me or on different shafts, in such positions that they impart to the pistons amotion in opposite directions.

The pipe a, which connects the two cylinders, is provided with a valve, f, inserted in the bottom of the large cylinder and made to open outward, and with a valve, 7c, inserted in the bottom of the small cylinder and made to open inward. A pipe, h, the inner end of which is closed by a valve, t', leads to the large cylinder, and another pipe, j, connects with the small cylinder, the opening leading from said cylinder to this pipe being closed by a valve,

g, which opens outward.

The two cylinders are surrounded by jackets l l', which communicate with each other by'a pipe, m, anda current of liquid, drawn from the well or forced in by an additional pump,

n, is made to pass through these jackets for the purpose of keeping the cylinders A C cool. The operation is as follows: When the large piston rises the cylinder A fills with air, and

at the same time the small cylinder descends, and the air contained therein is forced through the pipe j into the well or reservoir. On the downstroke of the large piston the air contained in the large cylinder is forced through the pipe a into the small cylinder, and, if the area of the large piston is four times as large as that of the small piston, while the stroke of both is the same, the air contained in the large cylinder, on being forced into the small cylinder, is compressed tofour times its density; or, in other Words, if the pressure of the air in the large cylinderis tifteen pounds to the square inch, its pressure will be sixty pounds to the square inch after it has been forced into the small cylinder. On the next downstroke of the small piston the compressed air contained in the small cylinder is forced into the well or reservoir, and the powerV requisite for operating the pump is materially reduced, as previously explained.

By thecompression of the air the cylinders are liable to heat, and in order to prevent this the jackets are applied, and a current of liquid,

passing through said jackets, keeps the cylinders cool.

When the pump is used for the purpose of forcing air down into an oil-well against the pressure of the gases existing therein7 the oil ejected from the Well is made to pass through the jackets 5 but if the pump is used for the purpose of compressing air in a reservoir, the

additional pump, n, serves to force the requisite quantity of liquid through the jackets to keep the cylinders cool.

What I claim as new, and desire to secure by Letters Patent, is- Y l. Apump composed of two (or more) cylinders of unequal size, provided with pistons connected together by a pipe with suitable valves, as shown, in combination with an airsupply pipe leading to the largest and a discharge-pipe leading from the smallest cylinder, substantially as and for the purpose herein set forth.

2. The jackets l Z', communicating with each other by a pipe, m, and provided with a supply and discharge pipe, in combination with the cylinders A C, and with or Without an ad' ditional pump, n, substantially as and for the purpose described.

l J. N. DENNISSON.

Vitnesses:

WILLIAM HAYDEN, ROBERT LANG. 

